U.S. patent application number 10/362502 was filed with the patent office on 2004-03-04 for compositions adapted for chain linking.
Invention is credited to Carter, Jeffrey Thomas, McGrail, Patrick Terence.
Application Number | 20040044141 10/362502 |
Document ID | / |
Family ID | 9898045 |
Filed Date | 2004-03-04 |
United States Patent
Application |
20040044141 |
Kind Code |
A1 |
McGrail, Patrick Terence ;
et al. |
March 4, 2004 |
Compositions adapted for chain linking
Abstract
A polymer composition comprising chains of at least one aromatic
polymer or a mixture thereof together with at least one chain
linking component wherein the at least one aromatic polymer
comprises polymer chains of number average molecular weight (Mn) in
a first range and characterised by a polymer flow temperature, and
having at least one reactive end group, and wherein the at least
one chain linking component comprises at least two linking sites,
characterised in that a plurality of the polymer chain end groups
are adapted to react with the linking sites at chain linking
temperature in excess of the polymer flow temperature to form
linked polymer chains of number average molecular weight (Mn) in a
second range which is in excess of the first range, substantially
thermoplastic in nature; process for the preparation thereof;
prepreg, composite or shaped product obtained therewith and the use
thereof.
Inventors: |
McGrail, Patrick Terence;
(Cleveland, GB) ; Carter, Jeffrey Thomas;
(Cleveland, GB) |
Correspondence
Address: |
Fran S Wasserman
1937 West Main Street
P O Box 60
Stamford
CT
06904
US
|
Family ID: |
9898045 |
Appl. No.: |
10/362502 |
Filed: |
May 22, 2003 |
PCT Filed: |
August 20, 2001 |
PCT NO: |
PCT/GB01/03729 |
Current U.S.
Class: |
525/390 |
Current CPC
Class: |
C08G 81/00 20130101;
C08G 75/23 20130101; C08L 81/06 20130101 |
Class at
Publication: |
525/390 |
International
Class: |
C08G 065/48 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 22, 2000 |
GB |
0020620.1 |
Claims
1. A polymer composition comprising chains of at least one aromatic
polymer or a mixture thereof together with at least one chain
linking component wherein the at least one aromatic polymer
comprises polymer chains of number average molecular weight (Mn) in
a first range and characterised by a polymer flow temperature, and
having at least one reactive end group, and wherein the at least
one chain linking component comprises at least two linking sites,
characterised in that a plurality of the polymer chain end groups
are adapted to react with the linking sites at chain linking
temperature in excess of the polymer flow temperature to form
linked polymer chains of number average molecular weight (Mn) in a
second range which is in excess of the first range, substantially
thermoplastic in nature.
2. A polymer composition as claimed in claim 1 in the form of a
precursor composition comprising an amount of at least one aromatic
polymer as hereinbefore defined, together with an amount thereof,
which has been prereacted at chain terminating conditions with the
at least one chain linking component as hereinbefore defined to
form polymer chains of Mn in the first range, characterised by a
polymer flow temperature and having its reactive end groups
terminated with linking component, characterised in that a
plurality of the polymer chain reactive end groups are adapted to
react with the linking sites of linking component terminated
polymer chains at chain linking temperature in excess of the
polymer flow temperature to form linked polymer chains of number
average molecular weight (Mn) in a second range which is in excess
of the first range.
3. A polymer composition as claimed in any of claims 1 & 2
wherein flow temperature is the temperature at which the polymer
attains a suitably molten or fluid state to enable a degree of
polymer chain mobility to orient or align itself for reaction.
4. A polymer composition as claimed in any of claims 1 to 3 wherein
the chain linking temperature is higher than a product processing
temperature, to remove solvent and improve wet out of the
prepreg.
5. A polymer composition as claimed in any of claims 1 to 4 wherein
the number average molecular weight of the polyaromatic in the
second range is in the range 9000 to 60000, for example 11000 to
25000, and in the first range is in the range of 2000 to 11000, for
example in the range of 3000 to 9000.
6. A polymer composition as claimed in any of claims 1 to 5 which
comprises a first and second polymers having the same polymer
backbone but different end groups, both being amorphous; or
comprises a first aromatic polymer having a lower flow temperature
than a second similar aromatic polymer, both being amorphous the
second polymer being rendered in flowable form in the presence of
the first polymer in fluid form, thereby providing a processing
aid; or comprises an amorphous polymer and a crystalline or semi
crystalline polymer having a characteristic melting point, the semi
crystalline polymer being rendered flowable by solvent effect of
the first polymer, acting as a cosolvent, diluent, dispersant,
carrier or the like for the second aromatic polymer.
7. A polymer composition as claimed in any of claims 1 to 6 wherein
Reactive end groups (Y) and chain linking sites (Z) are selected
from any functional groups providing active hydrogen and any polar
functional group adapted to react at elevated temperature in the
presence of an electrophile, preferably selected from active H, OH,
NH.sub.2, NHR or SH wherein R is a hydrocarbon group containing up
to 8 carbon atoms, epoxy, (meth)acrylate, iso)cyanate, isocyanate
ester, acetylene or ethylene as in vinyl or allyl, maleimide,
anhydride, carboxylic acid, oxazoline and monomers containing
unsaturation; preferably reactive end groups Y are selected from
active H, OH, NH.sub.2, NHR or SH and chain linking sites Z are
selected from epoxy, (meth)acrylate, (iso)cyanate, isocyanate
ester, acetylene or ethylene as in vinyl or allyl, maleimide,
anhydride, carboxylic acid, oxazoline and monomers containing
unsaturation.
8. A polymer composition as claimed in any of claims 1 to 7 wherein
a chain linking component is of the formula B(Z)n(Z')n' wherein B
is a polymer chain or is a carbon atom backbone having from 1 to 10
carbon atoms, more preferably is an oligomer or polymer or is an
aliphatic, alicyclic or aromatic hydrocarbon optionally substituted
and/or including heteroatoms N,S,O or is a single bond or nucleus
such as C, O, S, N or Transition metal; Z and Z' are each
independently selected from functional groups as hereinbefore
defined for Z; n and n' are each zero or a whole number integer
selected from 1 to 6; and the sum of n and n' is at least 2,
preferably 2 to 10,000, more preferably 2 to 10 or 10 to 500 or 500
to 10000.
9. A polymer composition as claimed in any of claims 1 to 8 wherein
a chain linking component comprises a compound of formula
B(Z)nwherein B and Z are as hereinbefore defined in claim 8 and n
is selected from 2 to 6.
10. A polymer composition as claimed in and of claims 1 to 9
wherein a linear or branched polymer chain having at least two ends
comprises at least two reactive end groups and comprises a diol,
polyol, diamine, polyamine, dithiol or polythiol or the like and a
chain linking component comprises at least two linking sites
whereby at least two polymer chains may be linked together, and
comprises a diepoxy, polyepoxy, di(meth)acrylate,
poly(meth)acrylate, di(iso)cyanate, poly(iso)cyanate, diacetylene,
polyacetylene, dianhydride, polyanhydride, dioxazoline,
polyoxazoline.
11. A polymer composition as claimed in any of claims 1 to 10
wherein linking components are selected from the structures:
8Benzophenone tetra carboxylic acid dianhydride (BTDA) 9Maleic
anhydride having units 10
12. A polymer composition as claimed in any of claims 1 to 11
wherein a polymer chain reactive end group is hydroxy and
corresponds to a linking site functionality which is epoxy, whereby
reaction thereof produces a .beta. hydroxy ether linkage in
polymers of increased number average molecular weight having either
hydroxy or epoxy end groups as desired; or the reactive end group
is NH.sub.2 and the linking site functionality is anhydride,
whereby reaction thereof produces an imide linkage in polymers of
increased number average molecular weight having NH.sub.2 or
anhydride end groups; or the reactive end group is NH.sub.2 and the
linking site functionality is maleimide.
13. A polymer composition as claimed in any of claims 1 to 12
wherein the reactive end groups and linking sites are present,
calculated by the amount of polymer chain and linking component, in
the required stoichiometric amounts to enable up to 100% linking of
polymer chains in multiples of two (binary linking), three
(tertiary linking), four (ternary linking), for example in a "star"
architecture, and combinations thereof.
14. A polymer composition as claimed in any of claims 1 to 13
wherein an amount of additional intra or inter chain functionality
is provided in the form of functional groups along the chain length
whereby the chain linking component is selected to provide such
functionality, selected from solvent resistance (F), cross-linking
grafting sites (unsaturated groups), Tg enhancing or
compatibilising agents eg a microstructure compatible and reactive
with another polymer.
15. A polymer composition as claimed in any of claims 1 to 14
wherein the at least one polyaromatic comprises ether-linked and/or
thioether-linked repeating units, the units being selected from the
group consisting of --(PhAPh).sub.n--and optionally
additionally--(Ph).sub.a--wherein A is SO.sub.2 or CO, Ph is
phenylene, n=1 to 2, a=1 to 4 and when a exceeds 1, said phenylenes
are linked linearly through a single chemical bond or a divalent
group other than --A-- or are fused together directly or via a
cyclic moiety such as a cycloalkyl group, a (hetero) aromatic
group, or cyclic ketone, amide, amine, or imine, said at least one
polyarylsulphone having reactive pendant and/or end groups.
16. A polymer composition as claimed in any of claims 1 to 15
wherein the at least one polyaromatic comprises at least one
polyaryl sulphone comprising ether-linked repeating units,
optionally additionally comprising thioether-linked repeating
units, the units being selected from the group consisting
of--(PhSO.sub.2Ph).sub.n--and optionally
additionally--(Ph).sub.a--wherein Ph is phenylene, n=1 to 2, a=1 to
3 and when a exceeds 1, said phenylenes are linked linearly through
a single chemical bond or a divalent group other than --SO.sub.2--
or are fused together, provided that the repeating unit
--(PhSO.sub.2Ph).sub.n-- is always present in said at least one
polyarylsulphone in such a proportion that on average at least two
of said units --(PhSO.sub.2Ph).sub.n-- are in sequence in each
polymer chain present, said at least one polyarylsulphone having
reactive pendant and/or end groups.
17. A polymer composition as claimed in any of claims 1 to 16
wherein the polyaromatic comprises polyether sulphone, more
preferably a combination of polyether sulphone and polyether ether
sulphone linked repeating units, in which the phenylene group is
meta- or para- and is preferably para and wherein the phenylenes
are linked linearly through a single chemical bond or a divalent
group other than sulphone, or are fused together.
18. A polymer composition as claimed in claims 16 and 17 wherein
the units are: I X Ph SO.sub.2 Ph X Ph SO.sub.2 Ph ("PES") and II X
(Ph)a X Ph SO.sub.2 Ph ("PEES") where X is 0 or S and may differ
from unit to unit; the ratio is I to II (respectively) preferably
between 10:90 and 80:20 such as between 35:65 and 65:35.
19. A polymer composition as claimed in claims 16 to 18 wherein
relative is proportions of the repeating units of the
polyarylsulphone expressed in terms of the weight percent SO.sub.2
content, defined as 100 times (weight of SO.sub.2)/(weight of
average repeat unit) is at least 22, preferably 23 to 25%. When a=1
this corresponds to PES/PEES ratio of at least 20:80, preferably in
the range 35:65 to 65:35.
20. A polymer composition as claimed in claims 1 to 19 additionally
comprising a thermoset polymer component selected from the group
consisting of an epoxy resin, an addition-polymerisation resin,
especially a bis-maleimide resin, a formaldehyde condensate resin,
especially a formaldehyde-phenol resin, a cyanate resin, an
isocyanate resin, a phenolic resin and mixtures of two or more
thereof.
21. A polymer composition as claimed in claim 20 wherein the weight
proportion of thermoplast component in the composition is typically
in the range 5 to 100%, preferably 5 to 90%, especially 5 to 50,
for example 5 to 40%.
22. A process for the preparation of a polymer composition
comprising at least one aromatic polymer or a mixture thereof, the
process comprising: i) providing polyaromatic polymer chains having
Mn in a first range as hereinbefore defined and characterised by a
polymer flow temperature, wherein the at least one polyaromatic
polymer chains have at least one reactive end group, and ii)
providing at least one chain linking component having at least two
linking sites as hereinbefore defined, and iii) admixing at a first
temperature which is less than the chain linking temperature at
which the reactive end group and linking sites are adapted to react
as hereinbefore defined.
23. A process as claimed in claim 22 wherein admixing is carried
out at or below the composition flow temperature employed for
shaping the composition, and shaping is carried out simultaneously
or subsequently.
24. A process as claimed in any of claims 22 and 23 wherein the
polymers are prepared from monomers obtained and isolated with the
use of first and second fluids in the substantial absence of an
effective amount of azeotrope.
25. A process as claimed in claim 24 wherein the monomers are
prepared in a preselected Mn and as the monomers are in solution
introducing alternative end groups by reaction in the solution
prior to isolation thereof.
26. A process as claimed in claim 24 or 25 wherein first fluid
comprises at least one dipolar aprotic solvent, optionally present
in a fluid mixture with other liquids or non liquids, which acts to
promote the polymerisation reaction, preferably selected from one
or more of sulphur oxides, such as sulphoxides and sulphones,
formamides, pyrrolidones, cyclic ketones and the like, and the
second fluid is selected from alcohols and demineralised water or
demineralised aqueous solvents and mixtures thereof.
27. A process as claimed in any of claims 24 to 26 wherein the
polymer is as claimed in claims 16 to 19, wherein monomer
precursors are selected according to the desired polymer
composition comprising polyethersulphones to
polyetherethersulphones in a desired ratio employing respective
proportions of bisphenol and dihalides to monophenol in the same
molar amounts in the range of 10:90-100:0, preferably
10:90-70:30.
28. A process as claimed in any of claims 24 to 27 wherein reactive
end groups are introduced at the outset with the monomer polymer
precursors.
29. A process as claimed in any of claims 24 to 28 wherein end
groups comprising halo or hydroxy reactive groups are obtained by
addition of an excess of a component as hereinbefore defined in
claim 27 providing the repeating units of the polyarylsulphone, for
example in the form of a dihalide or a bisphenol and monophenol;
alternatively end groups comprising amino reactive groups may be
obtained by addition of a pre-determined amount of a monomer, which
does not provide repeating units of the polyarylsulphone, for
example of aminophenol.
30. A process for providing a composition as hereinbefore defined
in any of claims 1 to 21, as a shaped article or film, such as
impregnated, moulded, injection moulded, extruded or the like
articles or cast, sprayed or rollered films, comprising obtaining
the composition according to the invention as hereinbefore defined,
subjecting to a first temperature as hereinbefore defined
corresponding to the flow temperature of the unreacted composition
and shaping according to known techniques, optionally in solution
of a suitable solvent, subjecting to a second elevated temperature
as hereinbefore defined corresponding to the temperature for chain
linking reaction of the composition and obtaining a shaped article
or film having increased number average molecular weight in a
second range as hereinbefore defined.
31. A process as claimed in claim 30 wherein processing conditions
comprise elevated temperature in the range of 150-400.degree. C.
more preferably 175-300.degree. C., for example 190-250.degree.
C.
32. A resin composition as claimed in any of claims 1 to 21 for
fabrication of structures, including load-bearing or impact
resisting structures, containing a reinforcing agent such as
fibres.
33. A prepreg comprising a composition as hereinbefore defined in
any of claims 1 to 21 and continuous fibres, obtained by a process
as hereinbefore defined.
34. A composite comprising a pre-preg as hereinbefore defined in
claim 33 laminated together by heat and pressure, for example by
autoclave, compression moulding, or by heated rollers, at a
temperature above the curing temperature of the polymer
composition.
35. A thermoplast or a thermoplast-modified thermoset resin shaped
product comprising a composition, pre-preg, laminar composite or
shaped product as hereinbefore defined in any of claims 1 to 21, 33
to 35 and, which is obtained by the method as hereinbefore defined
in claim 30 or 31, for use in transport such as aerospace,
aeronautical, marine or automotive industries, rail and coach
industries or in building/construction industry, or for use in
non-high performance transport applications, non-construction
applications and adhesive applications, including high temperature
adhesive applications.
36. A composition, pre-preg, laminar composite or shaped product as
hereinbefore described or illustrated in the description and
figures.
Description
[0001] The present invention relates to polymer compositions,
prepregs, laminar composites and shaped articles adapted for chain
linking in manner to increase the number average molecular weight
thereof, a process for the preparation and shaping thereof, a
process for the chain linking thereof. Specifically the present
invention relates to polyaromatic compositions, prepregs, laminar
composites and shaped articles.
[0002] The use of curable compositions such as epoxy, cyanate,
phenolic and like resins, both reinforced and unreinforced, has
been known for a long time in a wide variety of structural
commercial and military applications. In constructing sports
devices, building materials, aeronautical, land and nautical
vehicles, light weight carbon-based tough materials have been found
to give enhanced performance. Moreover these compositions are found
to have uses as high temperature curing adhesives.
[0003] More recently, classes of polyaromatic compositions
comprising polyaryl thermoplastic components containing ether-
and/or thioether-linked repeating units in the form of polyether
aromatics and polyetherether aromatics are known for the
manufacture of engineering polymers and composites having unique
properties in terms of strength, fracture toughness, modulus and
high temperature stability and resistance. In particular the
semi-crystalline polyaryl components have excellent solvent
resistance properties.
[0004] These polymer compositions are typically prepared at
temperatures in excess of their crystalline melt temperature, e.g.
in the range of up to 365.degree. C., formed with autoclaving into
prepregs, composites or shaped articles and subsequently processed
at elevated temperature and/or with use of a curing agent. There is
a trade off between the advantageous solvent resistance of
semi-crystalline compositions and their high processing
temperature. It would therefore be advantageous to be able to
provide semi-crystalline compositions which may be processed at
lower temperatures, whereby their use could become more accessible
for manufacture of articles.
[0005] The quality of prepregs, composites or shaped articles
obtained with these compositions is dependent on a number of
factors, not least the rheology thereof, in terms of ease and
uniformity of impregnation, molding or shaping, together with
ability to be retained in impregnated, molded or shaped form
without distortion prior to and during processing of impregnated,
molded or shaped articles.
[0006] Typically there is a trade off between providing
compositions with sufficiently low viscosity to enable complete and
accurate impregnation, molding or shaping thereof but with
acceptable mechanical properties in processed form, against an
excessively high viscosity at which impregnation, molding and
shaping performance deteriorates excessively.
[0007] Attempts to improve processing and mechanical performance of
such compositions have focussed on modification of the nature of
components, for example, including a blend of thermoplast and
thermoset components to optimise the processed mechanical
properties or modification of the method for impregnating, molding
or shaping, for example, in solution of a suitable solvent which
may subsequently be evaporated prior to processing. These attempts,
however introduce further problems in terms of morphology control,
solvent resistance and void formation for example.
[0008] In "Polyaromatics", P. T. McGrail, Polymer International 41
(1996) 103-121, polyaromatics and their synthesis and properties
are reviewed. In particular the above problems in terms of
prepregging, for example from solution, and properties of processed
prepregs are discussed with reference to block copolymers
comprising blocks of distinct polymer types linked via reactive
pendant groups and functionalised polyaromatics having reactive
groups adapted for cross-linking are discussed. This comprehensive
review of currently available techniques discloses the compromises
which must be made and problems which are encountered in the
manufacture of engineering polymers from fluid compositions.
[0009] We have now surprisingly found however that polymer
compositions may be provided which overcome the problems described
above in admirable manner, having excellent Theological properties
for prepregging, molding and shaping into articles, combined with
excellent mechanical and solvent resistance properties as
engineering polymers.
[0010] Accordingly a first object of the present invention is to
provide polyaromatic compositions for making molded, impregnated or
otherwise shaped articles for which mechanical properties of
processed molded, impregnated or otherwise shaped articles may be
controlled independently of constraints imposed by rheology
required for effective injection molding, impregnation or shaping
to form articles.
[0011] A second object of the present invention is to provide
polyaromatic compositions prepared in a calculated molecular weight
range of polymer which may be achieved independently of constraints
imposed by the preparation process, such as solubility constraints
and the like.
[0012] A third object of the present invention is to provide
polyaromatic compositions with a desired level of uniform mobility
to provide a desired increase in number average molecular weight on
further reaction thereof.
[0013] A fourth object of the present invention is to provide high
quality injection molded, impregnated or otherwise shaped articles
of essentially thermoplastic polymers obtained with improved
properties of finished articles and having improved solvent
resistance properties without the commonly associated high
processing temperatures required for molding, impregnation or
otherwise shaping thereof.
[0014] In its broadest aspect there is provided according to the
present invention aromatic polymer compositions having rheology
adapted for impregnation, is molding or otherwise shaping and being
adapted for subsequent reactive chain linking thereof to provide
polymer compositions of increased molecular weight which are
substantially thermoplastic in nature.
[0015] Specifically there is provided according to the present
invention a polymer composition comprising chains of at least one
aromatic polymer or a mixture thereof together with at least one
chain linking component wherein the at least one aromatic polymer
comprises polymer chains of number average molecular weight (Mn) in
a first range and characterised by a polymer flow temperature, and
having at least one reactive end group, and wherein the at least
one chain linking component comprises at least two linking sites,
characterised in that a plurality of the polymer chain end groups
are adapted to react with the linking sites at chain linking
temperature in excess of the polymer flow temperature to form
linked polymer chains of number average molecular weight (Mn) in a
second range which is in excess of the first range, substantially
thermoplastic in nature.
[0016] The polymer composition as hereinbefore defined may be
adapted for prereaction to form a precursor composition comprising
an amount of at least one aromatic polymer as hereinbefore defined,
together with an amount thereof, which has been prereacted at chain
terminating conditions with the at least one chain linking
component as hereinbefore defined to form polymer chains of Mn in
the first range, characterised by a polymer flow temperature and
having its reactive end groups terminated with linking component,
characterised in that a plurality of the polymer chain reactive end
groups are adapted to react with the linking sites of linking
component terminated polymer chains at chain linking temperature in
excess of the polymer flow temperature to form linked polymer
chains of number average molecular weight (Mn) in a second range
which is in excess of the first range.
[0017] Flow temperature is defined as the temperature at which the
polymer attains a suitably molten or fluid state to enable a degree
of polymer chain mobility to orient or align itself for
reaction.
[0018] Chain linking temperature is defined as the temperature at
which the polymer chain ends reaction is initiated. Preferably the
chain linking temperature is higher than a product processing
temperature, to remove solvent and improve wet out of the prepreg
which leads to better quality prepreg with easier handling
characteristics.
[0019] Chain terminating conditions may be selected such that self
reaction is avoided, ie whereby the chain termination does not
develop into a chain linking reaction.
[0020] The composition is adapted for shaping with reduced physical
void formation as a result of the greater and more uniform mobility
of the composition having Mn in a first range. This is particularly
advantageous and enables high through put laminate production
without temperature ramping or degassing.
[0021] The difference in first and second Mn ranges is defined as
the increase at which a desired extent of reaction is achieved by
means of choice of stoichiometry, reaction time or temperature at
which mobility decreases as a result of reaction below that for
polymer chains to align themselves for further reaction. It will be
appreciated therefore that the second Mn range may be controlled by
selection of stoichiometry or reaction time or of chain linking
temperature with respect to the flow temperature and with respect
to any postcure temperature applied.
[0022] The number average molecular weight of the polyaromatic in
the second range is suitably in the range 9000 to 60000. A useful
sub-range is for example 11000 to 25000, and in the first range is
suitably in the range of 2000 to 11000, especially in the range of
3000 to 9000.
[0023] The composition may comprise an additional solvent for the
polymer chains whereby a reduced flow temperature may be attained.
Preferably the composition comprises substantially no solvent and
is adapted for flow and chain linking in the absence of any solvent
or effective amount thereof. It is a particular advantage that
compositions comprising no solvent are adapted to retain the
polymer chain morphology in the chain linked form.
[0024] It is a particular advantage of the invention that the
compositions are adapted for forming articles at low temperature
due to their flowable rheology in unreacted form giving excellent
moulding, impregnation wet out or shaping complexity (with
injection moulding), and in reacted form having number average
molecular weight in a second range as hereinbefore defined they are
characterised by mechanical and thermal properties corresponding to
known compositions comprising polymer chains having number average
molecular weight in the second range as hereinbefore defined. This
allows the use of cheaper bagging, moulding, tie-down or other
ancillary materials.
[0025] Preferably compositions comprising two or more aromatic
polymers comprise a first and second polymers having the same
polymer backbone but different end groups, both being amorphous, or
comprise a first aromatic polymer having a lower flow temperature
than a second similar aromatic polymer, both being amorphous the
second polymer being rendered in flowable form in the presence of
the first polymer in fluid form, thereby providing a processing
aid, or comprise an amorphous polymer and a semi crystalline
polymer having a characteristic melting point, the semi crystalline
polymer being rendered flowable by solvent effect of the first
polymer, and is not truly molten at a temperature below that at
which it is normally processable as determined by its
characteristic melting point.
[0026] More preferably a second aromatic polymer is
(semi)crystalline and is rendered in flowable form by solvating
action of a first amorphous aromatic polymer. Accordingly the first
aromatic polymer may act as a cosolvent, diluent, dispersant,
carrier or the like for the second aromatic polymer. This is of
particular advantage in enabling the preparation of multiblock
compositions having lowered processing temperatures whilst
nevertheless retaining excellent product properties such as solvent
resistance. It is of significance that the product exhibits
(semi)crystalline morphology, which is responsible for excellent
solvent resistance of some product polymers of the invention.
[0027] Reactive end groups and chain linking sites as hereinbefore
defined are suitably any functional groups adapted to be inert at
low temperature and to mutually react at elevated temperature in
manner to link the polymer chains and linking component and effect
chain linking. End groups and chain linking sites may be the same,
in the case of self reacting functionalities, or may be different
in the case of different reacting functionalities.
[0028] Reactive end groups (Y) and chain linking sites (Z) are
selected from any functional groups providing active hydrogen and
any polar functional group adapted to react at elevated temperature
in the presence of an electrophile, preferably selected from active
H, OH, NH.sub.2, NHR or SH wherein R is a hydrocarbon group
containing up to 8 carbon atoms, epoxy, (meth)acrylate,
iso)cyanate, isocyanate ester, acetylene or ethylene as in vinyl or
allyl, maleimide, anhydride, carboxylic acid, oxazoline and
monomers containing unsaturation; preferably reactive end groups Y
are selected from active H, OH, NH.sub.2, NHR or SH and chain
linking sites Z are selected from epoxy, (meth)acrylate,
(iso)cyanate, isocyanate ester, acetylene or ethylene as in vinyl
or allyl, maleimide, anhydride, carboxylic acid, oxazoline and
monomers containing unsaturation.
[0029] Preferably a chain linking component is of the formula
B(Z)n(Z')n' wherein B is a polymer chain or is a carbon atom
backbone having from 1 to 10 carbon atoms, more preferably is an
oligomer or polymer or is an aliphatic, alicyclic or aromatic
hydrocarbon optionally substituted and/or including heteroatoms
N,S,O or is a single bond or nucleus such as C, O, S, N or
Transition metal; Z and Z' are each independently selected from
functional groups as hereinbefore defined for Z;
[0030] n and n' are each zero or a whole number integer selected
from 1 to 6; and
[0031] the sum of n and n' is at least 2, preferably 2 to 10,000,
more preferably 2 to 10 or 10 to 500 or 500 to 10000.
[0032] More preferably a chain linking component is selected from
the formula B(Z)n wherein B and Z are as hereinbefore defined and n
is selected from 2 to 6.
[0033] Accordingly it will be apparent that self reaction between
methacrylate ended polymer and chain linking component or between
maleimide ended polymer and chain linking component or between
oxazoline ended polymer and chain linking component for example is
possible and within the scope of the present invention.
[0034] It is possible that a small amount of polymer chains and
chain linking component have mixed reactive end groups and chain
linking sites, ie one of each of the above defined groups, whereby
in a relatively mobile early stage of the chain linking reaction,
the end groups and sites are able to seek each other out by
alignment of the polymer chains and chain linking components.
Preferably however reactive end groups are of one type and chain
linking components are of a second type.
[0035] A polymer chain comprises at least one reactive end group
whereby at least one end may be linked to other polymer chains.
Preferably a linear or branched polymer chain having at least two
ends comprises at least two reactive end groups. Reactive end
groups may be the same or different and are preferably the same,
whereby a polymer chain is termed a diol, polyol, diamine,
polyamine, dithiol or polythiol or the like.
[0036] A chain linking component comprises at least two linking
sites whereby at least two polymer chains may be linked together.
Preferably a chain linear-linking component comprises two linking
sites, and a chain network-linking component such as a "star"
architecture linking component comprises at least three linking
sites. Linking sites may be the same or different and are
preferably the same, whereby a linking component is termed a
diepoxy, polyepoxy, di(meth)acrylate, poly(meth)acrylate,
di(iso)cyanate, poly(iso)cyanate, diacetylene, polyacetylene,
dianhydride, polyanhydride, dioxazoline, polyoxazoline or the
like.
[0037] A chain linking component is therefore selected from any
component which is capable of supporting multiple functionality in
close proximity, in manner that the multiple functional groups are
capable of reaction. The component comprises a carbon atom backbone
or polymer chain linking the linking sites as hereinbefore defined,
and linking site may be supported as pendant and/or end groups of a
linear, cyclic or combined linear-cyclic backbone.
[0038] In a further aspect of the invention there is therefore
provided a novel chain linking component as hereinbefore defined.
Preferred linking components are selected from the structures:
1
[0039] Benzophenone tetra carboxylic acid dianhydride (BTDA) 2
[0040] Maleic anhydride having units 3
[0041] In one preferred embodiment the reactive end group is
hydroxy and corresponds to a linking site functionality which is
epoxy, whereby reaction thereof produces a .beta. hydroxy ether
linkage in polymers of increased number average molecular weight
having either hydroxy or epoxy end groups as desired.
Alternatively, the reactive end group is NH.sub.2 and the linking
site functionality is anhydride, whereby reaction thereof produces
an imide linkage in polymers of increased number average molecular
weight having NH.sub.2 or anhydride end groups. Alternatively the
reactive end group is NH.sub.2 and the linking site functionality
is maleimide. Mixtures of the above may be employed to produce a
mixed architecture including a plurality of reactive end
group-linking site combinations.
[0042] Aromatic polymer chains have at least one reactive end group
as hereinbefore defined, and linking components have at least two
linking sites. The reactive end groups and linking sites may be
present, calculated by the amount of polymer chain and linking
component, in the required stoichiometric amounts to enable up to
100% linking of polymer chains in multiples of two (binary
linking), three (tertiary linking), four (ternary linking), for
example in a "star" architecture, and combinations thereof.
Preferably amounts are calculated to give 80-100% linking, more
preferably 90-100% linking, most preferably 95-100% linking, for
example substantially 100% linking, or may be present with one or
other in excess.
[0043] An amount of a single ended or end capping component or
polymer chain may be present to end cap the linked chains, and may
be the same or different from the polymer chain or linking
component.
[0044] Compositions comprising more than one aromatic may comprise
aromatics each having a different type of end groups or may
comprise all aromatics having the same type(s) of end groups as
hereinbefore defined. One or more chain linking components may be
provided with the same or different linking site functionality.
[0045] Preferably each polymer chain present in the composition has
reactive end groups of the same type whereby reaction can take
place without any specific orientation of polymer chains with
respect to chain linking component. It is a particular advantage
that polymer chains may be to an extent self-orientating in that
reactive end groups of the polymer chains have an affinity for
linking sites of the chain linking component.
[0046] Block copolymers may be generated by chain linking different
polymer chain types, having the same or different reactive end
groups, adapted to alternate in desired manner.
[0047] An amount of additional intra or inter chain functionality
may be provided in the form of functional groups along the chain
length. Accordingly the chain linking component may be selected to
provide such functionality, for example as solvent resistance (F),
cross-linking grafting sites (unsaturated groups), Tg enhancing or
compatibilising agents eg a microstructure compatible and reactive
with another polymer.
[0048] It is a particular advantage that the compositions of the
invention may be provided in distinct forms having characteristic
number average molecular weight as hereinbefore defined.
[0049] Preferably the at least one polyaromatic comprises same or
different repeating units of the formula 4
[0050] wherein A is selected from SO.sub.2, a direct link, oxygen,
sulphur, --CO-- and a divalent hydrocarbon radical;
[0051] X is a divalent group;
[0052] R is any one or more substituents of the aromatic rings,
each independently selected from hydrogen, C.sub.1-8 branched or
straight chain aliphatic saturated or unsaturated aliphatic groups
or moieties optionally comprising one or more heteroatoms selected
from O, S, N, or halo for example Cl or F; and groups providing
active hydrogen especially OH, NH.sub.2, NHR-- or --SH, where R--
is a hydrocarbon group containing up to eight carbon atoms, or
providing other cross-linking activity especially epoxy, (meth)
acrylate, cyanate, isocyanate, acetylene or ethylene, as in vinyl,
allyl or maleimide, anhydride, oxazoline and monomers containing
unsaturation; and
[0053] wherein said at least one polyaromatic comprises reactive
pendant and/or end groups preferably selected from reactive
heteroatoms, heteroatom containing or cross-linking groups as
defined for R.
[0054] Suitably the at least one polyaromatic comprises
ether-linked and/or thioether-linked repeating units, the units
being selected from the group consisting of
--(PhAPh).sub.n--
[0055] and optionally additionally
--(Ph).sub.n--
[0056] wherein A is SO.sub.2, or CO, Ph is phenylene, n=1 to 2, a=1
to 4 and when a exceeds 1, said phenylenes are linked linearly
through a single chemical bond or a divalent group other than --A--
or are fused together directly or via a cyclic moiety such as a
cycloalkyl group, a (hetero) aromatic group, or cyclic ketone,
amide, amine, or imine, said at least one polyarylsulphone having
reactive pendant and/or end groups.
[0057] More preferably the at least one polyaromatic comprises at
least one polyaryl sulphone comprising ether-linked repeating
units, optionally additionally comprising thioether-linked
repeating units, the units being selected from the group consisting
of
--(PhSO.sub.2Ph).sub.n--pos
[0058] and optionally additionally
--(Ph).sub.a--
[0059] wherein Ph is phenylene, n=1 to 2, a=1 to 3 and when a
exceeds 1, said phenylenes are linked linearly through a single
chemical bond or a divalent group other than --SO.sub.2-- or are
fused together, provided that the repeating unit
--(PhSO.sub.2Ph).sub.n-- is always present in said at least one
polyarylsulphone in such a proportion that on average at least two
of said units --(PhSO.sub.2Ph).sub.n-- are in sequence in each
polymer chain present, said at least one polyarylsulphone having
reactive pendant and/or end groups.
[0060] Preferably the polyaromatic comprises polyether sulphone,
more preferably a combination of polyether sulphone and polyether
ether sulphone linked repeating units, in which the phenylene group
is meta- or para- and is preferably para and wherein the phenylenes
are linked linearly through a single chemical bond or a divalent
group other than sulphone, or are fused together. By "fractional"
reference is made to the average value for a given polymer chain
containing units having various values of n or a.
[0061] Additionally, as also discussed, in said at least one
polyarylsulphone, the relative proportions of the said repeating
units is such that on average at least two units
(PhSO.sub.2Ph).sub.n are in immediate mutual succession in each
polymer chain present and is preferably in the range 1:99 to 99:1,
especially 10:90 to 90:10, respectively. Typically the ratio is in
the range 25-50 or more preferably in the range 75-50 (Ph).sub.a,
balance (Ph SO.sub.2Ph).sub.n. In preferred polyarylsulphones the
units are:
[0062] I X Ph SO.sub.2 Ph X Ph SO.sub.2 Ph ("PES") and
[0063] II X (Ph).sub.a X Ph SO.sub.2 Ph ("PEES")
[0064] where X is O or S and may differ from unit to unit; the
ratio is I to II (respectively) preferably between 10:90 and 80:20
especially between 10:90 and 55:45, more especially between 25:75
and 50:50; or the ratio is between 20:80 and 70:30, more preferably
between 30:70 and 70:30, most preferably between 35:65 and
65:35.
[0065] The flow temperature of polyetherethersulphone is generally
less than that of a corresponding Mn polyethersulphone, but both
possess similar mechanical properties. Accordingly the ratio may be
determined, by determining a and n above.
[0066] In copending UK patent application no. 9803714.6 is
disclosed a process for the obtaining such compositions from their
monomer precursors in manner to isolate the monomer precursors in
selected molecular weight as desired.
[0067] The preferred relative proportions of the repeating units of
the polyarylsulphone may be expressed in terms of the weight
percent SO.sub.2 content, defined as 100 times (weight of
SO.sub.2)/(weight of average repeat unit). The preferred SO.sub.2
content is at least 22, preferably 23 to 25%. When a=1 this
corresponds to PES/PEES ratio of at least 20:80, preferably in the
range 35:65 to 65:35.
[0068] The above proportions refer only to the units mentioned. In
addition to such units the polyarylsulphone may contain up to 50
especially up to 25% molar of other repeating units: the preferred
SO.sub.2 content ranges (if used) then apply to the whole polymer.
Such units may be for example of the formula 5
[0069] as hereinbefore defined, in which A is a direct link,
oxygen, sulphur, --CO-- or a divalent hydrocarbon radical. When the
polyarylsulphone is the product of nucleophilic synthesis, its
units may have been derived for example from one or more bisphenols
and/or corresponding bisthiols or phenol-thiols selected from
hydroquinone, 4,4'-dihydroxybiphenyl, resorcinol,
dihydroxynaphthalene (2,6 and other isomers),
4,4'-dihydroxybenzophenone, 2,2'-di(4-hydroxyphenyl)propane and
-methane.
[0070] If a bis-thiol is used, it may be formed in situ, that is, a
dihalide as described for example below may be reacted with an
alkali sulphide or polysulphide or thiosulphate.
[0071] Other examples of such additional units are of the formula
6
[0072] in which Q and Q', which may be the same or different, are
CO or SO.sub.2; Ar is a divalent aromatic radical; and n is 0, 1,
2, or 3, provided that n is not zero where Q is SO.sub.2. Ar is
preferably at least one divalent aromatic radical selected from
phenylene, biphenylene or terphenylene. Particular units have the
formula 7
[0073] where m is 1, 2 or 3. When the polymer is the product of
nucleophilic synthesis, such units may have been derived from one
or more dihalides, for example selected from
4,4'-dihalobenzophenone, 4,4'bis(4-chlorophenylsulphonyl)biphenyl,
1,4,bis(4-halobenzoyl)benzene and
4,4'-bis(4-halobenzoyl)biphenyl.
[0074] They may of course have been derived partly from the
corresponding bisphenols.
[0075] The polyaromatic may be the product of nucleophilic
synthesis from halophenols and/or halothiophenols. In any
nucleophilic synthesis the halogen if chlorine or bromine may be
activated by the presence of a copper catalyst.
[0076] Such activation is often unnecessary if the halogen is
activated by an electron withdrawing group. In any event fluoride
is usually more active than chloride. Any nucleophilic synthesis of
the polyaromatic is carried out preferably in the presence of one
or more alkali metal salts, such as KOH, NaOH or K.sub.2CO.sub.3 in
up to 10% molar excess over the stoichiometric.
[0077] As previously mentioned, said at least one polyaromatic
contains reactive end groups. Reactive end groups may be obtained
during the preparation from monomers or by conversion from polymers
having non-reactive end groups or having a different type of end
groups.
[0078] The polyaromatic of the invention may be further combined
with additional polymers in reactive or non reactive manner, for
example polyimides, polyolefins (polypropylene PP,
polyphenyleneoxide PPO, polyvinylchloride PVC), acrylics, aromatic
polyesters (polyethyl teraphalate PET) or thermoplast or thermoset
polymers as hereinbefore described. For example the polyaromatic
may be reacted with polyimide, semicrystalline PET/PEK, PEG or
siloxane for enhanced Tg, solvent resistance and the like.
[0079] Thermoset polymers may be selected from the group consisting
of an epoxy resin, an addition-polymerisation resin, especially a
bis-maleimide resin, a formaldehyde condensate resin, especially a
formaldehyde-phenol resin, a cyanate resin, an isocyanate resin, a
phenolic resin and mixtures of two or more thereof, and is
preferably an epoxy resin derived from the mono or polyglycidyl
derivative of one or more of the group of compounds consisting of
aromatic diamines, aromatic monoprimary amines, aminophenols,
polyhydric phenols, polyhydric alcohols, polycarboxylic acids and
the like, or a mixture thereof, a cyanate ester resin or a phenolic
resin. Examples of addition-polymerisation resins are acrylics,
vinyls, bis-maleimides, and unsaturated polyesters. Examples of
formaldehyde condensate resins are urea, melamine and phenols.
[0080] Preferably the thermoset polymer comprises at least one
epoxy, cyanate ester or phenolic resin precursor, which is liquid
at ambient temperature for example as disclosed in EP-A-0 311 349,
EP-A-0 365 168, EPA 91310167.1 or in PCT/GB95/0 1303.
[0081] An epoxy resin may be selected from N,N,N'N'-tetraglycidyl
diamino diphenylmethane (eg "MY 9663", "MY 720" or "MY 721" sold by
Ciba-Geigy) viscosity 10-20 Pa s at 50.degree. C.; (MY 721 is a
lower viscosity version of MY720 and is designed for higher use
temperatures);
N,N,N',N'-tetraglycidyl-bis(4-aminophenyl)-1,4-diiso- propylbenzene
(eg Epon 1071 sold by Shell Chemical Co) viscosity 18-22 Poise at
110.degree. C.;
N,N,N',N'-tetraglycidyl-bis(4-amino-3,5-dimethylphenyl)-1,4-diisoprop-
ylbenzene, (eg Epon 1072 sold by Shell Chemical Co) viscosity 30-40
Poise at 110.degree. C.; triglycidyl ethers of p-aminophenol (eg
"MY 0510" sold by Ciba-Geigy), viscosity 0.55-0.85 Pa s at
25.degree. C.; preferably of viscosity 8-20 Pa at 25.degree. C.;
preferably this constitutes at least 25% of the epoxy components
used; diglycidyl ethers of bisphenol A based materials such as
2,2-bis(4,4'-dihydroxy phenyl) propane (eg "DE R 661" sold by Dow,
or "Epikote 828" sold by Shell), and Novolak resins preferably of
viscosity 8-20 Pa s at 25.degree. C.; glycidyl ethers of phenol
Novolak resins (eg "DEN 431" or "DEN 438" sold by Dow), varieties
in the low viscosity class of which are preferred in making
compositions according to the invention; digylcidyl 1,2-phthalate,
eg GLY CEL A-100; diglycidyl derivative of dihydroxy diphenyl
methane (Bisphenol F) (eg "PY 306" sold by Ciba Geigy) which is in
the low viscosity class. Other epoxy resin precursors include
cycloaliphatics such as 3',4'-epoxycyclohexyl-3,-
-4-epoxycyclohexane carboxylate (eg "CY 179" sold by Ciba Geigy)
and those in the "Bakelite" range of Union Carbide Corporation.
[0082] A cyanate ester resin may be selected from one or more
compounds of the general formula NCOAr(Y.sub.xAr.sub.m).sub.qOCN
and oligomers and/or polycyanate esters and combinations thereof
wherein Ar is a single or fused aromatic or substituted aromatics
and combinations thereof and therebetween nucleus linked in the
ortho, meta and/or para position and x=0 up to 2 and m and q=0 to 5
independently. The Y is a linking unit selected from the group
consisting of oxygen, carbonyl, sulphur, sulphur oxides, chemical
bond, aromatic linked in ortho, meta and/or para positions and
CR.sub.1R.sub.2 wherein R.sub.1 and R.sub.2 are hydrogen,
halogenated alkanes, such as the fluorinated alkanes and/or
substituted aromatics and/or hydrocarbon units wherein said
hydrocarbon units are singularly or multiply linked and consist of
up to 20 carbon atoms for each R.sub.1 and/or R.sub.2 and
P(R.sub.3R.sub.4R'.sub.4R.sub.5) wherein R.sub.3 is alkyl, aryl,
alkoxy or hydroxy, R'.sub.4 may be equal to R.sub.4 and is a singly
linked oxygen or chemical bond, R.sub.5 is doubly linked oxygen or
chemical bond and Si(R.sub.3R.sub.4R'.sub.4R.sub.6) wherein R.sub.3
and R.sub.4, R'.sub.4 are defined as in
P(R.sub.3R.sub.4R'.sub.4R.sub.5) above and R.sub.5 is defined
similar to R.sub.3 above. Optionally, the thermoset can consist
essentially of cyanate esters of phenol/formaldehyde derived
Novolaks or dicyclopentadiene derivatives thereof, an example of
which is XU71787 sold by the Dow Chemical Company.
[0083] A phenolic resin may be selected from any aldehyde
condensate resins derived from aldehydes such as methanal, ethanal,
benzaldehyde or furfuraldehyde and phenols such as phenol, cresols,
dihydric phenols, chlorphenols and C.sub.1-9 alkyl phenols, such as
phenol, 3- and 4-cresol (1-methyl, 3- and 4-hydroxy benzene),
catechol (2-hydroxy phenol), resorcinol (1,3-dihydroxy benzene) and
quinot (1,4-dihydroxy benzene). Preferably phenolic resins comprise
cresol and novolak phenols.
[0084] The thermoset polymer is suitably the product of at least
partly curing a resin precursor using a curing agent and optionally
a catalyst.
[0085] The weight proportion of thermoplast component in the
composition is typically in the range 5 to 100%, preferably 5 to
90%, especially 5 to 50, for example 5 to 40%.
[0086] The thermoset and polyarylaromatic are suitably reacted in
the presence of a curing agent to provide a resin composition. The
curing agent is suitably selected from any known curing agents, for
example as disclosed in EP-A-0 311 349, EPA 91310167.1, EP-A-0 365
168 or in PCT/GB95/01303, which are incorporated herein by
reference, such as an amino compound having a. molecular weight up
to 500 per amino group, for example an aromatic amine or a
guanidine derivative. Particular examples are 3,3'- and
4-,4'-diaminodiphenylsulphone, (available as "DDS" from commercial
sources), methylenedianiline, bis(4-amino-3,5-dimethylphenyl)--
1,4-diisopropylbenzene (available as EPON 1062 from Shell Chemical
Co); bis(4-aminophenyl)-1,4-diisopropylbenzene (available as EPON
1061 from Shell Chemical Co); 4-chlorophenyl-N,N-dimethyl-urea, eg
Monuron; 3,4-dichlorophenyl-N,N-dimethyl-urea, eg Diuron and
dicyanodiamide (available as "Amicure CG 1200 from Pacific Anchor
Chemical). Other standard epoxy curing agents such as aliphatic
diamines, amides, carboxylic acid anhydrides, carboxylic acids and
phenols can be used if desired. If a novolak phenolic resin is used
as the main thermoset component a formaldehyde generator such as
hexamethylenetetraamine (HMT) is typically used as a curing
agent.
[0087] Conventionally, and as described in EP-A-0 311 349 or in
PCT/GB95/01303, a catalyst for the epoxy resin component/curing
agent reaction may also be used, typically a Lewis acid or a
base.
[0088] In a further aspect there is provided according to the
present invention a process for the preparation of a polymer
composition comprising at least one aromatic polymer or a mixture
thereof, the process comprising:
[0089] i) providing polyaromatic polymer chains having Mn in a
first range as hereinbefore defined and characterised by a polymer
flow temperature, wherein the at least one polyaromatic polymer
chains have at least one reactive end group, and
[0090] ii) providing at least one chain linking component having at
least two linking sites as hereinbefore defined, and
[0091] iii) admixing at a first temperature which is less than the
chain linking temperature at which the reactive end group and
linking sites are adapted to react as hereinbefore defined.
[0092] The admixing may be carried out at or below the composition
flow temperature employed for shaping the composition, and shaping
may be carried out simultaneously or subsequently.
[0093] The chain linking component may be prepared by
interconversion from the corresponding component to introduce
linking sites, or may be prepared by a dedicated synthesis.
[0094] In a further aspect of the invention there is therefore
provided a process for the preparation of a chain linking component
as hereinbefore defined by interconversion from the corresponding
component to introduce a plurality of linking sites.
[0095] The polymers of the composition may be prepared from polymer
precursors comprising monomers in the presence of a reactive
component adapted to provide the desired reactive end group, or may
be prepared by interconversion from the polymer having a different
type of end group by reaction with a component adapted to provide
the desired reactive end groups. Processes for the preparation of
polyaromatics are disclosed in "Polyaromatics", P. T. McGrail,
Polymer International 41(1996) 103-121 as hereinbefore referred,
the contents of which are incorporated herein by reference.
[0096] In one preferred embodiment, the polymers are prepared from
monomers obtained and isolated with the use of first and second
fluids in the substantial absence of an effective amount of
azeotrope, according to copending UK patent application number
9803714.6, the contents of which are incorporated herein by
reference.
[0097] It is of particular advantage that the process according to
this embodiment enables the preparation of polymers with convenient
isolation thereof from by-products of the reaction, by
precipitation from the reaction mixture. This has the advantage
that the polymer may be prepared in a relatively low number average
molecular weight in a first range as hereinbefore defined, without
incurring problems in purification thereof, or loss of yield on
isolation.
[0098] In a particular advantage of the present invention, the
monomers can be prepared according to the abovementioned process in
a preselected Mn and with desired end groups. As the monomers are
in solution it is possible to introduce alternative end groups by
reaction in the solution prior to isolation thereof to form polymer
chains of a composition according to the present invention.
[0099] In fact the use of the abovementioned preferred process in
obtaining polymer compositions having a number average molecular
weight in a first range for impregnation, molding or shaping which
is substantially less than that which has been commonly employed in
the art previously, enables the preparation in excellent manner of
impregnated, molded or shaped articles of excellent quality.
[0100] The first fluid suitably comprises at least one dipolar
aprotic solvent, optionally present in a fluid mixture with other
liquids or non liquids, which acts to promote the polymerisation
reaction, preferably selected from one or more of sulphur oxides,
such as sulphoxides and sulphones, formamides, pyrrolidones, cyclic
ketones and the like.
[0101] Preferably the second fluid is any fluid displaying the
required solvent properties, for example is selected from alcohols
and demineralised water or demineralised aqueous solvents and
mixtures thereof.
[0102] The relative amounts of monomer precursors may be selected
according to the desired polymer composition. A composition
comprising polyethersulphones to polyetherethersulphones in a
desired ratio may therefore be obtained by employing respective
proportions of bisphenol and dihalides to monophenol in the same
molar amounts. Preferably the proportion of bisphenol and dihalide
to monophenol is in the range of 10:90-100:0, preferably
30:70-70:30, providing the polyarylsulphone having PES:PEES of the
same proportions.
[0103] Preferably reactive end groups are introduced at the outset
with the polymer precursors. This has the advantage of avoiding the
need to open up the reactor at a later quenching stage, which risks
disturbing the reaction and introducing gaseous contaminants such
as oxygen and the like. Moreover without being limited to this
theory it is thought that the presence of reactive end groups
throughout the process may lead to controlled and stable polymer
chain growth which is as a result of self regulation of chain
length. Such self regulation may take the form of continuous growth
of chains with simultaneous chain scission.
[0104] Alternatively reactive end groups may be added in a further
amount of first fluid to the reacted polymer precursors at a
further elevated temperature for a further period. This has the
advantage of quenching the reaction mixture to halt the further
development of molecular weight.
[0105] Reactive end groups may be the same as or different to a
polymer precursor as hereinbefore defined. End groups comprising
halo or hydroxy reactive groups may be obtained by addition of an
excess of a component as hereinbefore defined providing the
repeating units of the polyarylsulphone, for example employing a
slight molar excess of the dihalide or the bisphenol and
monophenol. This has the advantage of convenience and accuracy of
handling the minimum number of components. Alternatively end groups
comprising amino reactive groups may be obtained by addition of a
pre-determined amount of a monomer, which does not provide
repeating units of the polyarylsulphone, for example of
aminophenol. This has the advantage of dedicated control of end
group stoichiometry and molecular weight development. The
composition may be isolated in the form of a solid phase
precipitate which may be purified and dried as hereinbefore defined
and according to known techniques. The precipitate may be further
processed to a useable physical form, for example extruded into
pellets, drawn or spun as fibres or films and the like, in
particular as disclosed in copending GB 0020630 the contents of
which are incorporated herein by reference.
[0106] The polymer chains obtained may be further converted to
derivatives or analogues of the polyaromatic by reaction with a
suitable functionalising or derivatising agent. For example the end
groups may be modified by providing the polymer chains in the
reaction solution, or post-isolation, in a solution of a suitable
solvent together with any functionalising or derivatising agent
according to known techniques.
[0107] In a further aspect of the invention there is provided a
process for providing a composition as hereinbefore defined as a
shaped article or film, such as impregnated, moulded, injection
moulded, extruded or the like articles or cast, spayed or rollered
films, comprising obtaining the composition according to the
invention as hereinbefore defined, subjecting to a first
temperature as hereinbefore defined corresponding to the flow
temperature of the unreacted composition and shaping according to
known techniques, optionally in solution of a suitable solvent,
subjecting to a second elevated temperature as hereinbefore defined
corresponding to the temperature for chain linking reaction of the
composition and obtaining a shaped article or film having increased
number average molecular weight in a second range as hereinbefore
defined.
[0108] In the case that the composition is provided as fibre or
film, a pre-form shape may be provided at ambient temperature, for
example by weaving, or comingling fibres and the like, predisposed
to flow into a desired shape by melting or dissolving at flow
temperature.
[0109] Preferably processing conditions comprise elevated
temperature in the range of 150-400.degree. C. more preferably
175-300.degree. C., for example 190-250.degree. C. Processing
conditions may comprise atmospheric or elevated temperature adapted
to the reaction temperature as hereinbefore defined by gradual or
ramp increase from the flow temperature. It is a particular
advantage that processing may be conducted at atmospheric
pressure.
[0110] In a further aspect there is provided according to the
invention a resin formulation comprising polyaromatic polymer
chains and a chain linking component as hereinbefore defined.
[0111] A resin composition is particularly suitable for fabrication
of structures, including load-bearing or impact resisting
structures. For this purpose it may contain a reinforcing agent
such as fibres. Fibres can be added short or chopped typically of
mean fibre length not more than 2 cm, for example about 6 mm.
Alternatively, and preferably, the fibres are continuous and may,
for example, be unidirectionally-disposed fibres or a woven fabric,
ie the composite material comprises a prepreg. Combinations of both
short and/or chopped fibres and continuous fibres may be utilised.
The fibres may be sized or unsized. Fibres can be added typically
at a concentration of 5 to 35, preferably at least 20%, by weight.
For structural applications, it is preferred to use continuous
fibre for example glass or carbon, especially at 30 to 70, more
especially 50 to 70% by volume.
[0112] The fibre can be organic, especially of stiff polymers such
as poly paraphenylene terephthalamide, or inorganic. Among
inorganic fibres glass fibres such as "E" or "S" can be used, or
alumina, zirconia, silicon carbide, other compound ceramics or
metals. A very suitable reinforcing fibre is carbon, especially as
graphite. Graphite fibres which have been found to be especially
useful in the invention are those supplied by Amoco under the trade
designations T650-35, T650-42 and T300; those supplied by Toray
under the trade designation T800-HB; and those supplied by Hercules
under the trade designations AS4, AU4, IM 8 and IM 7.
[0113] Organic or carbon fibre is preferably unsized or is sized
with a material that is compatible with the composition according
to the invention, in the sense of being soluble in the liquid
precursor composition without adverse reaction or of bonding both
to the fibre and to the thermoset/thermoplastic composition
according to the invention. In particular carbon or graphite fibres
that are unsized or are sized with epoxy resin precursor or
thermoplast such as polyarylsulphone are preferred. Inorganic fibre
preferably is sized with a material that bonds both to the fibre
and to the polymer composition; examples are the organo-silane
coupling agents applied to glass fibre.
[0114] The composition may contain for example conventional
toughening agents such as liquid rubbers having reactive groups,
aggregates such as glass beads, rubber particles and rubber-coated
glass beads, filler such as polytetrafluorethylene, silica,
graphite, boron nitride, mica, talc and vermiculite, pigments,
nucleating agents, and stabilisers such as phosphates. The total of
such materials and any fibrous reinforcing agent in the composition
should be at least 20% by volume, as a percentage of the total
volume of the polysulphone/thermoset mixture. The percentages of
fibres and such other materials are calculated on the total
composition after reaction or processing at the hereinbelow defined
temperatures.
[0115] Preferably the composition is obtained as hereinbefore
defined, by mixing the polyaromatic, chain linking component,
thermoset precursor and (at some stage) any fibrous reinforcing
agent and other materials. A solvent may be present. The solvent
and the proportion thereof are chosen so that the mixture of
polymer and resin precursor form at least a stable emulsion,
preferably a stable apparently single-phase solution. The ratio of
solvent to polyaromatic is suitably in the range 5:1 to 20:1 by
weight. Preferably a mixture of solvents is used, for example of a
halogenated hydrocarbon and an alcohol, in a ratio suitably in the
range 99:1 to 85:15. Conveniently the solvents in such a mixture
should boil at under 100.degree. C. at 1 atm pressure and should be
mutually miscible in the proportions used.
[0116] Preferably however a solvent is not present and the
polyaromatic, chain linking component and thermoset or precursor
are brought together at Mn in a first range avoiding the need for
hot melting and/or high shear mixing.
[0117] The mixture is stirred until sufficiently homogeneous.
Thereafter any solvent is removed by evaporation to give a resin
composition. Evaporation is suitably at 50-200.degree. C. and, at
least in its final stages, can be at subatmospheric pressure, for
example in the range 13.33 Pa to 1333 Pa (0.1 to 10 mm Hg). The
resin composition preferably contains up to 5% w/w of volatile
solvent, to assist flow when used to impregnate fibres. This
residual solvent will be removed in contact with the hot rollers of
the impregnating machine.
[0118] Suitably the composition in form of a resin solution is
transferred onto a suitable mould or tool for preparation of a
panel, prepreg or the like, the mould or tool having been preheated
to a desired degassing temperature.
[0119] The stable emulsion is combined with any reinforcing,
toughening, filling, nucleating materials or agents or the like,
and the temperature is raised to initiate flow and processing
thereof. Suitably processing is carried out at elevated temperature
up to 150.degree. C., preferably in the range of 100.degree. C. to
130.degree. C., more preferably at about 120.degree. C.-125.degree.
C., and with use of elevated pressure to restrain deforming effects
of escaping gases, or to restrain void formation, suitably at
pressure of up to 10 bar, preferably in the range of 3 to 7 bar
abs. Suitably the processing temperature is attained by heating at
up to 5.degree. C./min, for example 2.degree. C. to 3.degree.
C./min and is maintained for the required period of up to 9 hours,
preferably up to 6 hours, for example 3 to 4 hours. Pressure is
released throughout and temperature reduced by cooling at up to
5.degree. C./min, for example up to 3.degree. C./min.
[0120] It is an advantage that second stage processing is not
required to raise the glass transition temperature of the product
or otherwise. This is in view of the fact that the Tg is a function
of the original polymer architecture. Tg may be increased by
incorporation of functional linking components.
[0121] The resin composition, possibly containing some volatile
solvent already present or newly added, can be used for example as
an adhesive or for coating surfaces or for making solid structures
by casting possibly in a foamed state. Short fibre reinforcement
may be incorporated with composition prior to curing thereof.
Preferably a fibre-reinforced composition is made by passing
essentially continuous fibre into contact with such resin
composition. The resulting impregnated fibrous reinforcing agent
may be used alone or together with other materials, for example a
further quantity of the same or a different polymer or resin
precursor or mixture, to form a shaped article. This technique is
described in more detail in EP-A-56703, 102158 and 102159.
[0122] A further procedure comprises forming composition into film
by for example compression moulding, extrusion, melt-casting or
belt-casting, laminating such films to fibrous reinforcing agent in
the form of for example a non-woven mat of relatively short fibres,
a woven cloth or essentially continuous fibre in conditions of
temperature and pressure sufficient to cause the mixture to flow
and impregnate the fibres and subsequently processing the resulting
laminate.
[0123] The resulting multi-ply laminate may be anisotropic in which
the fibres are continuous and unidirectional, orientated
essentially parallel to one another, or quasi-isotropic in each ply
of which the fibres are orientated at an angle, conveniently
45.degree. as in most quasi-isotropic laminates but possibly for
example 30.degree. or 60.degree. or 90.degree. or intermediately,
to those in the plies above and below. Orientations intermediate
between anisotropic and quasi-isotropic, and combination laminates,
may be used. Suitable laminates contain at least 4 preferably at
least 8, plies. The number of plies is dependent on the application
for the laminate, for example the strength required, and laminates
containing 32 or even more, for example several hundred, plies may
be desirable. There may be aggregates, as mentioned above in
interlaminar regions. Woven fabrics are an example of
quasi-isotropic or intermediate between anisotropic and
quasi-isotropic.
[0124] In a further aspect of the invention there is provided the
use of a composite mould or tool, bagging material, and the like
conventionally used for thermoset materials, to contain or support
a composition according to the invention as hereinbefore defined
during the processing thereof. Preferably these are constructed of
any suitable unsaturated polyester or thermoset resin such as
bis-maleimides, nylon film and the like having a heat resistance in
excess of the processing temperature to be employed.
[0125] In a further aspect of the invention there is provided a
prepreg comprising a composition as hereinbefore defined and
continuous fibres, obtained by a process as hereinbefore
defined.
[0126] In a further aspect of the invention there is provided a
composite comprising pre-pregs as hereinbefore defined laminated
together by heat and pressure, for example by autoclave,
compression moulding, or by heated rollers, at a temperature above
the curing temperature of the polymer composition.
[0127] In a further aspect of the invention there is provided a
thermoplast or a thermoplast-modified thermoset resin shaped
product comprising a composition, pre-preg or laminar composite as
hereinbefore defined, which is obtained by the method as
hereinbefore defined. Preferably such product is for use in
transport such as aerospace, aeronautical, marine or automotive
industries, rail and coach industries or in building/construction
industry, or for use in non-high performance transport
applications, non-construction applications and adhesive
applications, including high temperature adhesive applications.
[0128] The invention is now illustrated in non limiting manner with
reference to the following examples.
EXAMPLE 1
[0129] Synthesis of 40:60 PES:PEES Copolymer, Hydroxy Terminated
and Calculated to Have a Molecular Weight of 7,000
[0130] Bisphenol-S (18.92 gms), Dichlorodiphenylsulphone (52.84
gms) and Hydroquinone (12.49 gms) were charged to a 3 necked round
bottomed flask. Sulpholane (194 mls) was added to the reactants.
The reaction flask was then flushed with nitrogen. The reactants
were stirred at RT whilst Potassium Carbonate (27.60 gms) was
added. After about 5 minutes heat was applied to the reactor using
an oil bath set at 180.degree. C. As the temperature rose the
reaction converting Hydroquinone and Bisphenol-S to bisphenates
proceeded, water and carbon dioxide were produced. The reaction was
held at 180.degree. C. for 30 minutes, and water was vented from
the reactor. The temperature was raised again to 205.degree. C. and
held for a further 60 minutes. Again during this period a large
amount of water was produced. The temperature was raised again to
225.degree. C. and the reaction was completed with a hold time of 4
hours.
[0131] Upon completion of the reaction the polymer solution was
cooled to less than 60.degree. C. and the polymer was precipitated
into stirring Methanol. The Sulpholane is extremely soluble in
Methanol, it is also extremely soluble in water. The polymer was
then filtered from the methanol and was then macerated, filtered
again and washed several times with water and dilute Acetic Acid
until the pH of the effluent was neutral. The polymer was then
dried at 100.degree. C. overnight.
[0132] As the bisphenate forms it reacts with the DCDPS by
displacing the chlorine group producing an ether link and Potassium
Chloride, as a byproduct. Bisphenate formation and the displacement
of the chlorine groups continues until all of the monomers have
been consumed and no more of the bisphenate remains. The resulting
polymer is hydroxy terminated and is shown in FIG. 3 (I).
Characterisation of this polymer can be seen in Table 4 found in
the appendices.
EXAMPLE 2
[0133] Synthesis of 40:60 PES:PEES Copolymer, Amine Terminated,
Calculated Molecular Weight 7000
[0134] Polymer was synthesised using the procedure described in
Example 1 and including m-aminophenol (1.75 gms) as monomer,
utilising Sulpholane as the polymerisation solvent, and using
calculated amount of monomers, such that the polymer was amine
terminated. It was not possible to get mechanical data for this due
to the brittle nature of the polymer. The structure is shown in
FIG. 1 (I).
EXAMPLE 3
[0135] Procedure for the Moulding of Chain Extended Thermoplastic
Neat Resin Panels
[0136] Amine Terminated 40:60 PES:PEES Copolymer Chain Extended
with Benzophenone Tetracarboxylic Dianhydride (BTDA).
[0137] The low Mn amine ended polymer of Example 2 (100 g) is
predissolved in NMP (250 ml) at RT. Upon dissolution the relative
amount of BTDA (8.63 g), required to endcap the amine groups (as
characterised in Table 4 of the appendices), is added and the blend
is warmed to about 50.degree. C. After about 30 minutes further
resin of Example 2 (50 g--ratio of BTDA terminated resin to amine
terminated resin was 2:1) is added to the solution. This forms a
blend of anhydride terminated polymer and amine terminated polymer
(FIG. I-II and I-), in predetermined ratio, the solution is then
precipitate into methanol. The precipitated polymer is then washed
several times and dried at 100.degree. C.
[0138] A 6".times.4".times.3 mm compression mould is then prewarmed
to 300.degree. C. as are the platens of a compression press. The
polymer is then taken from the oven at 100.degree. C. and added to
the compression mould which is placed into the press and the
platens closed. A pressure of 1 ton is applied initially and
allowed to reduce. This represents the melting and flowing of the
polymer blend. After about 10 minutes pressure is applied again
until small amounts of polymer flashing are seen coming from the
mould. This pressure is then sustained for about 1 hour, the mould
cooled to RT and pressure removed. The neat resin panel is removed.
Visual examination of the moulded neat resin part showed it to be
transparent and completely intact. Flashings from the side of the
panel were subjected to a simple "crease" test which demonstrated
its increased toughness over the polymer described in Example 2.
This polymer could not be creased to form a "hinge" due to its
brittle nature.
[0139] Measurements of flexural modulus, yield strength, fracture
strength and fracture toughness were made for different molar
ratios of polymer to chain linking component. The results are shown
in Table 1.
[0140] Gel Permeation Chromatography (GPC) was used to determine
the Mn (number average molecular weight) and the Mw (weight average
molecular weight) of the chain extended polymer and that of the
polymer from Example 2. The results are shown in FIG. 2, which
demonstrate the considerable change in molecular weight
distribution.
Comparative 1
[0141] Preparation of Polymer Composition Comprising 40:60 PES:PEES
Copolymer, Chlorine Terminated, Calculated Molecular Weight 20,000
Cured Into Neat Resin Casting
[0142] The high molecular weight chlorine terminated polymer was
synthesised using Hydroquinone (g), Bisphenol-S (g) and DCDPS (g)
Stoichiometry was such that the polymer was chlorine terminated.
The process for the polymerisation was carried out as described in
Example 1. Characterisation of the polymer can be seen in Table 4
of the appendices.
[0143] Neat resin compression castings were obtained using the
procedure as described in Example 3. Visual inspection of the
moulded neat resin panel showed it to be similar to that of the
chain extended polymer described under Example 3.
[0144] The mechanical properties were investigated. The results are
shown in Table 1.
Comparative 2
[0145] Preparation of Commercially Available 3600P Polymer
Composition Cured Into Neat Resin Casting
[0146] Commercially available 3600P was obtained and neat resin
casting obtained using the procedure as described in Example 3.
[0147] The mechanical properties were investigated. The results are
shown in Table 1. Characterisation of the polymer can be seen in
Table 4 of the appendices.
1TABLE 1 Mechanical properties of neat resins Glass Amine ended
tran- Flexural Fracture PES:PEES/ sition mod- Yield Fracture tough-
Exam- BTDA ended temp ulus strength strength ness ple PES:PEES
(.degree. C.) (GPa) (MPa) (MNm.sup.-3/2) (KJm.sup.-2) 3 1/2 226
3.05 123.7 1.95 1.55 3 1/1.5 227 2.8 122.2 2.16 1.9 3 1/1.25 230
3.19 125.05 2.21 1.95 C2 3600P PES 225 2.8 100 2 2 C1 Chlorine 225
3 120 2.15 2.2 terminated PES:PEES
[0148] This table demonstrates that the chain linked materials
produce identical neat resin mechanical properties to that of their
engineering commercial counterparts
EXAMPLE 4
[0149] Procedure for the Preparation of Prepreg and the Moulding of
Chain Extended Thermoplastic Composite Panels
[0150] Amine Terminated 40:60 PES:PEES Copolymer Chain Extended
with Benzophenone Tetracarboxylic Dianhydride (BTDA).
[0151] The low Mn amine ended polymer (500 g) is predissolved in
NMP (500 ml), at RT. Upon dissolution the relative amount of BTDA
(43.15 g), required to endcap the amine groups, is added and the
blend is warmed to about 50.degree. C.
[0152] After about 30 minutes further resin of Example 2 (250 g) is
added to the solution. This forms a blend of anhydride terminated
polymer and amine terminated polymer (FIG. 1-II & I), in
predetermined ration.
[0153] The polymer solution at an appropriate solids level is then
used for the solution impregnation of carbon fibre. In order to aid
the wetting of the carbon fibres the temperature of the
impregnation bath was kept at 100.degree. C. This is considerably
less than the temperature required to impregnate conventional high
molecular weight thermoplastics which are typically in the area of
400.degree. C. The fibre/resin/solvent mixture is then passed over
a series of heated rollers ranging in temperature from 150 to
220.degree. C. This is required to remove the NMP solvent. The
quality of the prepreg was excellent and showed good consolidation
of the fibre tows in the thermoplastic matrix. The solvent free
prepreg can then be used to prepare composite panels.
[0154] A 6".times.4".times.3 mm open cast mould is filled with a
number of layers of prepreg to prepare a defined configuration for
a particular mechanical test. The mould is then placed into a
vacuum bagging system, typical of the art, and placed into a
pressclave or autoclave. Vacuum is applied, to consolidate the
prepreg layers and the pressclave is then heated at a predetermined
rate to 300.degree. C. as the vacuum is removed. A suitable
processing cycle is then followed after which the cooled panel
cooled at predetermined cooling rate is removed. Quality assurance
testing was carried out to establish the consolidation of the
composite in terms of void content by sectioning and micrographic
observation. The fibre volume was established using acid etching.
The fibre volume was found to be 65% and the void content was
acceptable.
[0155] Measurements of transflexural strength and short beam shear
were made for different molar rations of polymer chain to chain
linking component. The results are shown in Table 2 and FIG. 1.
Comparative 3
[0156] Preparation of Prepreg of Commercially Available 5200P
[0157] Commercially available 5200P (a polyethersulphone
manufactured by Victrex), characterisation of this polymer can be
seen in Table 4 of the appendices, was impregnated onto carbon
fibres (AS4) using the solution impregnation route described in
Comparative 2, except in this case the NMP impregnation solution
had to be kept at 175.degree. C., in order to render the solution
viscosity low enough for impregnation purposes.
[0158] The quality of the resulting prepreg was inferior to that of
the material from Comparative 2 in that consolidation of the fibre
tows within the thermoplastic matrix was low resulting in fibre
tows breaking away from the unidirectional prepreg.
[0159] This polymer was also melt impregnated at 400.degree. C.
from a solid solvent, diphenylsulphone (DPS), typical of the art as
described in US patent no. 5374694 (EP 0 412 827 B)
[0160] Both prepregs were then used to prepare composite laminates
for the determination of Short Beam Shear (SBS) and Transflexural
Strength (TFS) the results of which can be seen in Table 2.
Comparative 4
[0161] Preparation of Prepreg of Commercially Available 3600P
[0162] Commercially available 3600P (a polyethersulphone
manufactured by Victrex), characterisation of this polymer can be
seen in Table 4 of the appendices, was impregnated onto carbon
fibres (AS4) using the solution impregnation route described in
Comparative 2, except in this case the NMP impregnation solution
had to be kept at 175.degree. C., in order to render the solution
viscosity low enough for impregnation purposes.
[0163] The quality of the resulting prepreg was inferior to that of
the material from Comparative 2 in that consolidation of the fibre
tows within the thermoplastic matrix was low resulting in fibre
tows breaking away from the uni-directional prepreg.
[0164] This polymer was also melt impregnated at 400.degree. C.
from a solid solvent, diphenylsulphone (DPS), typical of the art as
described in patent no. Both prepregs were then used to prepare
composite laminates for the determination of Short Beam Shear (SBS)
and Transflexural Strength (TFS) the results of which can be seen
in Table 2.
2TABLE 2 Mechanical properties (transflexural strength (TFS) and
short beam shear (SBS)) of prepregs Example Material (molar ratio)
TFS (MPa) SBS (MPa) 4 PES:PEES 24.6 70 4 Amine ended PES:PEES: 54.9
78 anhydride ended PES:PEES (1:2) 4 Amine ended PES:PEES: 98.2 83
anhydride ended PES:PEES (1:1.5) 4 Amine ended PES:PEES: 127.2 85
anhydride ended PES:PEES (1:1.25) C3 5200P (solution) 55 75 C3 5200
(melt) 95 69 C4 3600P (solution) 48 72 C4 3600 (melt) 94 87
EXAMPLE 5
[0165] Preparation of Diamine Ended PEK
[0166] 4,4'-fluorobenzophenone (27.51 g), 4,4'hydroxy benzophenone
(21.41 g), m-aminophenol (6.68 g) and potassium carbonate (18.32 g)
were reacted in diphenyl sulphone (147 g) to give a 1.5K amine
terminated PEK polymer the characterisation results of which can be
seen in Table 4 of the appendices. The reaction took several stages
to complete from the preparation of the potassium salts of
m-aminophenol and 4'-hydroxybenzophenone to the final
polymerisation stage.
[0167] The polymer was isolated into acetone and characterised
using .sup.1Hnmr and DSC, confirming that the polymer backbone was
PEK and that the end groups were >95% amine. DSC analysis showed
a single melting point sequence, a Tp at 353.degree. C. The product
structure is shown in FIG. 4 (II).
[0168] The level of crystallinity was measured using X-ray
diffraction (XRD) and Differential Scanning Calorimetry (DSC) and
was found to be in the range of 50-60%.
EXAMPLE 6
[0169] Preparation of APA/PEK Multiblocks
[0170] The anhydride ended APA of Example 3A., shown in FIG. 4(I)
was blended with the amine ended PEK of Example 5 (Mn 1500) in
NMP--the amine terminated PEK was extremely soluble in the APA/NMP
mixture and this was unexpected--and on dissolution the blended
polymer was precipitated into methanol and the purified blend
recovered.
[0171] The multiblock was prepared by heating the blend up to
310.degree. C. in a compression press for 60 minutes prior to the
application of pressure to press a thin film. The film was cooled
to rt using air and water blown through the platens of the
press.
[0172] The film was very opaque, indicating its crystalline nature,
and characterisation was by DSC. APA Mn was 10,000 and PEK Mn 1500.
The DSC showed a Tg of the multiblock occurring at 216.degree. C.,
Tp at 369.degree. C. with a level of crystallinity of 12%. The
product comprised repeating units as shown in FIG. 4 in the form of
a multiblock.
EXAMPLE 7
[0173] Chain Linking of Crystalline Diamine Ended PEK Polymer
Composition and Neat Resin Casting
[0174] An impregnation solution was prepared by synthesising the
anhydride ended s APA (63 g), using the polymer characterised from
Example 3 and found in Table 4, in NMP at 50.degree. C. using a
stoichiometric amount of BTDA as described in Example 3. The
previously synthesised amine ended PEK (7 g), characterisation of
this polymer can be found in Table 4 of the appendices, was then
added and allowed to dissolve. On dissolution the solution
containing 40% solids was used to impregnate AS4 carbon fibre tows.
The same conditions described earlier to impregnate the chain
extended system were utilised. Excellent looking prepreg was
produced having a fibre content of 64+/-2%. The product comprised
repeating units as shown in FIG. 4, having a constant value for a
and b--small amounts of the polymer flashings were used to
characterise the molecular weight of the chain extended polymer,
the results of which can be seen in Table 4.
[0175] TEM micrographs (FIGS. 5 and 6) show the morphology of the
amorphous crystalline phases of the resin casting of Example 7.
FIG. 5 at low magnification (13.8K) shows a range of crystalline
phases revealing various sizes and shapes. The lack of contrast
around the interface between amorphous and crystalline suggest a
good interface between the two phases. Further increased
magnification in FIG. 6 reveals a very well defined lamella
structure.
EXAMPLE 8
[0176] Preparation of Sample of Amorphous Amine Ended KM Polymer
Prepreg of Example 4 of the Invention--For the Assessment of the
Interlaminar Shear Strength (ILSS) Properties
[0177] ILSS sample was prepared from the prepreg of Example 4,
using the following procedure.
[0178] Prepreg was moulded in an autoclave into panels with
appropriate lay-up using a standard vacuum bag technique and the
following cure cycle:
[0179] heat to 125.degree. C. at 2.degree. C./min under pressure
between 3 and 7 bar abs;
[0180] hold 6 h while venting vacuum bag;
[0181] cool to rt at less than 3.degree. C./min.
EXAMPLE 9
[0182] Preparation of Sample of Semicrystalline Amine Ended KM PEK
Polymer Prepreg of Example 6 of the Invention--For the Assessment
of the Interlaminar Shear Strength (ILSS) Properties
[0183] ILSS sample was prepared from the prepreg of Example 7,
using the procedure of Example 8.
Comparative 5
[0184] Preparation of Sample of HTA/IM6, Chlorine Ended--For the
Assessment of the Interlaminar Shear Strength (ILSS) Properties
[0185] Interlaminar sample was prepared from a commercially
available chlorine ended Victrex polymer prepreg, using the
procedure of Example 8.
Comparative 6
[0186] Preparation of Sample of Low Mn HTA/MLW/IM6 Chlorine
Ended--For the Assessment of the Interlaminar Shear Strength (ILSS)
Properties
[0187] ILSS sample was prepared from a commercially available low
Mn chlorine ended Victrex polymer prepreg, using the procedure of
Example 8.
EXAMPLE 10
[0188] Solvent Resistance as Determined by the % Retention of ILSS
Properties of Processed Samples of the Invention
[0189] ILSS samples of the compositions of the invention obtained
in Examples 8 and 9 and Comparative 5 and 6 were exposed to
solvents and % retention of ILSS properties were determined.
[0190] The results are shown in Table 3
3TABLE 3 % Solvent Resistance of interlaminar samples Solvent
T/time C5 C6 8 9 MEK RT/1 hr 81% 0% 66% 77% JP8 RT/1000 hr 96% 60%
99% 85% JP8 70.degree. C./1000 hr 76% 54% 82% 65% Skydrol RT/1000
hr 36% 30% 36% 77% Skydrol 70.degree. C./1000 hr 28% 18% 22%
44%
[0191] From the results the sample of Examples 8 and 9 comprising
amorphous and semi-crystalline block copolymer showed excellent
properties in the Skydrol exposure test at room temperature for
1000 hours.
EXAMPLE 11
[0192] Tan Delta Measurements for Resins of Similar Mn
[0193] Rheology of samples of 9KPES, 9K PES:PEES and 9K amorphous
HTA were carried out using an RDS800 machine, all the polymers were
hydroxyl terminated and the characterisation of these polymers can
be seen in Table 4 of the appendices. The polymers were melted
between 40 mm diameter plates and the materials elastic and storage
moduli, viscosity and tan delta values, as a function of
temperature, were determined. The value of tan delta, which
measures the separation between the two moduli, is an indication of
the flow properties of the polymer. Maximum separation, that is
elastic moduli lying below the storage moduli would represent a
polymer with high flow properties. The results are shown in FIG.
7.
[0194] 9000 HTA is very inflexible and has flow temperature of
340.degree. C.
[0195] 9000PES has flow temperature of 300.degree. C.
[0196] 9000PES:PEES has flow temperature of 270.degree. C.,
coincident with the chain linking reaction.
[0197] The polymer thus starts to react while flowing and continues
to react, to give product having Mn in the second range determined
by the mobility of the polymer. A highly mobile polymer will have a
short reaction window and result in low Mn (second range) polymer,
compared to a less mobile polymer which has a long window of chain
linking reaction and results in high Mn (second range) polymer.
EXAMPLE 12
[0198] Tan Delta Measurements for Resins of Different Mn
[0199] The measurements of Example 11 were repeated for 40:60
PES:PEES resins, amine ended, having different Mn. The results are
shown in FIG. 8. FIG. 9 shows a plot of the maximum tan delta
against Mn as a linear relation. Viscosity measurements (FIG. 10)
are also shown to be regular for low Mn resins of the invention,
compared with the conventional Comparative 2.
EXAMPLE 13
[0200] Crystallinity Measurement
[0201] Comparison was made of multiblock PES:PEES compositions
having different Mn, in terms of their crystallinity. The results
indicated that crystallinity varies with Mn and can be as high as
25%. It was not possible to significantly affect crystallinity by
subjecting to elevated temperature.
[0202] The TEM shows crystalline phases of ordered stacked
chains.
[0203] Further advantages of the invention are apparent from the
foregoing.
* * * * *